496 SUMMARY OF CURRENT RESEARCHES RELATING TO 



London. In a similar manner an Optotechnical Institute, either at the 

 Northampton Polytechnic in Clerkenwell or elsewhere, should be or- 

 ganised. He sketches a scheme of studies, and dwells upon the 

 importance of the project. 



B. Technique.* 

 CD Collecting 1 Objects.iincluding- Culture Processes. 



Media for distinguishing B. coli, B. typhosus, and related 

 Species. f — A. S. Griinbaum and E. H. Hume have found that for ordi- 

 nary working purposes MacUonkey's medium with neutral red gives the 

 best results, but for demonstration purposes a medium containing both 

 neutral red and crystal violet gives very striking and instructive pic- 

 tures. The medium recommended has the following composition : — agar 

 2 grm. ; peptone 2 grin. ; water 100 ccm. ; made alkaline to the extent 

 of 0*4 ccm. normal NaOH beyond the neutral (litmus) point. To this, 

 when filtered and sterilised, are added, sod. taurocholate 0*5 grm.; 

 lactose 1 grm. ; ^ p.c. neutral red solution 1 ccm. The whole is steri- 

 lised for 15 minutes. In this medium B. coli and other lactose fermenters 

 grow as red colonies ; all other similar forms (B. typhosus, B. paracolon) 

 are white, and impart to the surrounding medium an amber or orange 

 tint. The authors also find that on lactose-agar to which both neutral 

 red and crystal violet (1-100,000) have been added B. coli is red and 

 B. typhosus blue to purple. 



Method for the Detection of the Typhoid Bacillus in the Blood. £ 

 — A. Castellani advocates the use of large quantities of nutrient broth 

 for isolating the typhoid bacillus from blood, on the ground that not only 

 the blood, but also the agglutinins it contained, would be greatly diluted, 

 and at the same time the bactericidal properties of the blood-serum 

 would be weakened. The technique merely consists in obtaining asepti- 

 cally a few cubic centimetres of blood and at once transferring to 

 large flasks (five or six) each containing at least 300 ccm. of faintly 

 alkaline beef-broth. The flasks are then incubated at blood heat. In 

 practice this method has been found to be very successful, not only by 

 the author, but by several other investigators. 



Polythermostats.§ — G. Gabritchewsky advocates the adoption of 

 combining in one apparatus several thermostatic chambers heated to 

 different temperatures by one and the same source of heat. The idea is 

 ingenious, and has been successfully carried out in Moscow, Berlin, and 

 Paris. 



Hanging-drop Cultivation.|| — G. C. Karop describes the following 

 convenient method for making hanging-drop cultures. The materials 

 required are millboard, slides, 1 in. square covers, a soup-plate and bell- 

 glass to fit it, white blotting-paper, and a strip or two of perforated zinc. 



* This subdivision contains (1) Collecting Objects, including Culture Pro- 

 cesses ; (2) Preparing Objects ; (3) Cutting, including Imbedding and Microtomes ; 

 (4) Staining and Injecting ; (5) Mounting, including slides, preservative fluids, &c. ; 

 (6) Miscellaneous. t Brit. Med. Journ., 1902, i. pp. 1473-4 (1 fig.). 



X Centralbl. Bakt., l ta Abt., xxxi. (1902) pp. 477-9. § Tom. cit., pp. 814-6. 



|| Journ. Quek. Micr. Club, viii. (1902") pp. 2G5-7. 



